The significant growth in air traffic has led to a need for increasing synchronisation between the aircraft and the management of the traffic by air traffic controllers. This synchronisation requires, on the one hand, a capacity for temporal prediction of the trajectories by the equipment on board the aircraft, but also reliability in making these temporal predictions during the flight. Furthermore, the controllers have to ensure the separation and scheduling of the aircraft throughout the flight and, more particularly, in the approach phases. One of the options for ensuring the synchronisation and scheduling of the aircraft during the flight is to impose upon them one or more time constraints (RTA—Required Time of Arrival) during the flight.
These days, the flight management computers (Flight Management Systems) can take into account only a single time constraint, or, when several constraints can be entered into the flight plan, only the first is taken into account in computing the predictions and the speed setpoints (EP0637787), or else the constraints are activated individually (EP1800197). Furthermore, the methods for computing these speed predictions for making an RTA rely on iterative computations, which are difficult to manage for a number of simultaneous constraints.
When the time constraint is proposed in time interval form (earliest constraint, latest constraint, or a combination of the two), it is impossible to exploit this flexibility to choose a time of passage that makes it possible to make the subsequent constraints, or even optimises same.
Some existing methods such as (US 2012/0253650/FR1152604) make it possible to predict the possible times of passage of the aircraft at different points of the flight plan, by taking into account the preceding time constraints and the flight envelope of the aircraft. However, not one makes it possible to anticipate the constraints to impose times of passage that make it possible to ensure that the subsequent constraints are made.